1. Technical Field
Embodiments of the invention relate absorbent articles comprising an absorbent body, a liquid-permeable covering layer arranged over a first surface on the absorbent body, and a liquid-permeable liquid-transfer layer arranged between the absorbent body and the liquid-permeable covering layer.
2. Background Art
Disposable absorbent articles, such as diapers, incontinence pads, bed protectors, sanitary towels, etc., which are intended to receive and absorb bodily discharges such as urine, menstrual blood and motions have been well known for a long time. Absorbent articles of this kind usually comprise a liquid-permeable covering layer and a liquid-impermeable covering layer, with an absorbent body enclosed between the covering layers. Especially in the case of urine absorption, it is essential in this connection that the absorbent article and, in particular, the liquid-permeable covering layer is capable of receiving and rapidly admitting liquid. It is also important for the surface of the article to be kept as dry as possible even after wetting and for liquid which has passed into the article to remain there and not leak back out towards the body of the user. This phenomenon is usually referred to as rewetting and is highly undesirable.
The requirements for rapid admission of liquid into an absorbent article and also a dry surface and low rewetting are in part incompatible. A close liquid-permeable covering material with fine pores therefore affords good protection against rewetting but leads to the liquid-admission capacity being low. This often results in liquid not being taken up by the absorbent article but instead running out on the surface of the article and causing leakage. Moreover, a fine-pored material tends to retain liquid after wetting, which makes the surface of the article feel wet. A coarse-pored surface material has a good capacity for rapidly admitting liquid and does not to any great extent retain liquid in the pores. On the other hand, such a material offers poor protection against rewetting. A loose material moreover has a low masking effect, which means that colored bodily fluid such as menstrual blood is clearly visible through the covering material.
In order to remedy the abovementioned problems, it has been proposed to combine different types of liquid-permeable material. EP 0 312 118, for example, describes an absorbent article with a liquid-permeable covering layer arranged over the absorbent body of the article and with a likewise liquid-permeable transport layer arranged between the surface layer and the absorbent body. The transport layer has lower hydrophilicity than the absorbent body and moreover has an effective average pore size which is smaller than the pore size in the surface layer.
U.S. Pat. No. 5,968,855 describes a nonwoven material which is stated to have good liquid-transport properties and can be used as a transport layer in an absorbent article.
In spite of great efforts having been made in order to improve the liquid-permeable covering layer on an absorbent article, it has hitherto not been possible for an optimum combination of covering material and liquid-transfer material to be presented. A main object of the invention is therefore to offer an improved surface material combination, which makes possible both rapid liquid admission and a dry surface with low rewetting.